Blockchain Applications and Ethereum Interactions

The Interaction We're Discussing

First, it's essential to clarify that Ethereum is a decentralized platform, meaning it won't create new interaction interfaces for individual projects.

Here, "interaction" refers to applications interacting with on-chain smart contracts—specifically, how off-chain applications like Chainlink, Arbitrum, and Cosmos interact with on-chain contracts.

Therefore, we won’t focus on the following methods:

• Wallet-based interaction: Bundling an application into a webpage and connecting a wallet (e.g., MetaMask) to interact with the blockchain.
• Manual transaction construction: Building a transaction (tx), signing it with a private key, and sending it directly to a blockchain endpoint.

While these methods work for simple calls (e.g., NFT creation), they fall short for complex interactions—such as Arbitrum's interactive single-step proofs, which require monitoring contract events, analyzing them, and constructing responses.

In such cases, wallets are insufficient, and manual transaction construction becomes cumbersome. Fortunately, Ethereum provides a dedicated toolchain for seamless interactions.

The Ethereum Toolchain

The core idea is converting Solidity contracts into Go classes while encapsulating call details. At the application layer (e.g., Arbitrum, Chainlink), developers only need to pass parameters without handling low-level operations.

Example: Arbitrum Integration

Generating Go Code

The code generator tool is located here:
👉 Arbitrum Nitro Solgen

Since Arbitrum relies on a chain Makefile, we can’t directly run gen.go. Instead, follow these steps:

1. Build the contracts:

   yarn --cwd contracts build  
   yarn --cwd contracts build:forge:yul  

   This generates a build directory containing compiled contract artifacts.

2. Path configuration:
   The generator looks for JSON files in:

   • contracts/build/contracts/src/*/*.sol/*.json
   • safe-smart-account/build/artifacts/contracts/*/*.sol/*.json

Once built, run the generator to produce Go bindings for your contracts.

Using the Generated Code

Each contract becomes a Go class with methods mapped to Solidity functions. For example:

// ChallengeLibTransactorRaw: Auto-generated low-level Go binding  
type ChallengeLibTransactorRaw struct {  
    Contract *ChallengeLibTransactor  
}  

// Solidity function mapped to Go  
func (_ChallengeManager *ChallengeManagerTransactor) OneStepProveExecution(  
    opts *bind.TransactOpts,  
    challengeIndex uint64,  
    selection ChallengeLibSegmentSelection,  
    proof []byte,  
) (*types.Transaction, error) {  
    return _ChallengeManager.contract.Transact(opts, "oneStepProveExecution", challengeIndex, selection, proof)  
}  

Key components:

• opts: Contains user metadata (signer, nonce, gas settings).
• backend: The Ethereum client handling transaction submission.

Parameter Structure

The TransactOpts struct includes:

type TransactOpts struct {  
    From      common.Address  // Sender address  
    Nonce     *big.Int        // Transaction nonce  
    Signer    SignerFn        // Signing method  
    Value     *big.Int        // Transaction value  
    GasPrice  *big.Int        // Gas price  
    GasFeeCap *big.Int        // EIP-1559 fee cap  
    GasTipCap *big.Int        // EIP-1559 tip cap  
    GasLimit  uint64          // Gas limit  
    NoSend    bool            // Skip sending the transaction  
}  

Ethereum Client Setup

The client (ContractBackend) is initialized when creating a contract instance:

func NewChallengeManager(address common.Address, backend bind.ContractBackend) (*ChallengeManager, error) {  
    contract, err := bindChallengeManager(address, backend, backend, backend)  
    if err != nil {  
        return nil, err  
    }  
    return &ChallengeManager{  
        ChallengeManagerCaller:      ChallengeManagerCaller{contract: contract},  
        ChallengeManagerTransactor:  ChallengeManagerTransactor{contract: contract},  
        ChallengeManagerFilterer:    ChallengeManagerFilterer{contract: contract},  
    }, nil  
}  

The backend implements Ethereum’s ContractBackend interface, handling calls, transactions, and event filtering.

FAQs

1. Why use Go bindings instead of direct wallet interactions?

Go bindings automate low-level tasks (ABI encoding, signing) and support complex workflows like event monitoring—ideal for Layer 2 solutions like Arbitrum.

2. How do I handle gas fees in TransactOpts?

Set GasFeeCap and GasTipCap for EIP-1559 transactions, or use GasPrice for legacy chains.

3. Can I use this for other Ethereum-compatible chains?

Yes! The toolchain works with any EVM-compatible network (e.g., Polygon, BSC).

4. What if my contract isn’t in the build directory?

Run yarn build or hardhat compile in your project to generate the artifacts.

👉 Explore Ethereum development tools for deeper integrations.